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Lucienne M, Gerlini R, Rathkolb B, Calzada-Wack J, Forny P, Wueest S, Kaech A, Traversi F, Forny M, Bürer C, Aguilar-Pimentel A, Irmler M, Beckers J, Sauer S, Kölker S, Dewulf JP, Bommer GT, Hoces D, Gailus-Durner V, Fuchs H, Rozman J, Froese DS, Baumgartner MR, de Angelis MH. Insights into energy balance dysregulation from a mouse model of methylmalonic aciduria. Hum Mol Genet 2023; 32:2717-2734. [PMID: 37369025 PMCID: PMC10460489 DOI: 10.1093/hmg/ddad100] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 05/25/2023] [Accepted: 06/19/2023] [Indexed: 06/29/2023] Open
Abstract
Inherited disorders of mitochondrial metabolism, including isolated methylmalonic aciduria, present unique challenges to energetic homeostasis by disrupting energy-producing pathways. To better understand global responses to energy shortage, we investigated a hemizygous mouse model of methylmalonyl-CoA mutase (Mmut)-type methylmalonic aciduria. We found Mmut mutant mice to have reduced appetite, energy expenditure and body mass compared with littermate controls, along with a relative reduction in lean mass but increase in fat mass. Brown adipose tissue showed a process of whitening, in line with lower body surface temperature and lesser ability to cope with cold challenge. Mutant mice had dysregulated plasma glucose, delayed glucose clearance and a lesser ability to regulate energy sources when switching from the fed to fasted state, while liver investigations indicated metabolite accumulation and altered expression of peroxisome proliferator-activated receptor and Fgf21-controlled pathways. Together, these shed light on the mechanisms and adaptations behind energy imbalance in methylmalonic aciduria and provide insight into metabolic responses to chronic energy shortage, which may have important implications for disease understanding and patient management.
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Affiliation(s)
- Marie Lucienne
- Division of Metabolism and Children’s Research Center, University Children’s Hospital Zurich, University of Zurich, 8032 Zurich, Switzerland
- radiz – Rare Disease Initiative Zurich, Clinical Research Priority Program for Rare Diseases, University of Zurich, Zurich, Switzerland
- Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Raffaele Gerlini
- Institute of Experimental Genetics and German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Birgit Rathkolb
- Institute of Experimental Genetics and German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
- Institute of Molecular Animal Breeding and Biotechnology, Gene Center, Ludwig-Maximilians-University München, Munich, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Julia Calzada-Wack
- Institute of Experimental Genetics and German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Patrick Forny
- Division of Metabolism and Children’s Research Center, University Children’s Hospital Zurich, University of Zurich, 8032 Zurich, Switzerland
| | - Stephan Wueest
- Division of Pediatric Endocrinology and Diabetology and Children’s Research Center, University Children's Hospital, University of Zurich, 8032 Zurich, Switzerland
| | - Andres Kaech
- Center for Microscopy and Image Analysis, University of Zurich, Zurich, Switzerland
| | - Florian Traversi
- Division of Metabolism and Children’s Research Center, University Children’s Hospital Zurich, University of Zurich, 8032 Zurich, Switzerland
| | - Merima Forny
- Division of Metabolism and Children’s Research Center, University Children’s Hospital Zurich, University of Zurich, 8032 Zurich, Switzerland
| | - Céline Bürer
- Division of Metabolism and Children’s Research Center, University Children’s Hospital Zurich, University of Zurich, 8032 Zurich, Switzerland
| | - Antonio Aguilar-Pimentel
- Institute of Experimental Genetics and German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Martin Irmler
- Institute of Experimental Genetics and German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Johannes Beckers
- Institute of Experimental Genetics and German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Sven Sauer
- Division of Pediatric Neurology and Metabolic Medicine, Center for Pediatric and Adolescent Medicine, University Hospital, Heidelberg, Germany
| | - Stefan Kölker
- Division of Pediatric Neurology and Metabolic Medicine, Center for Pediatric and Adolescent Medicine, University Hospital, Heidelberg, Germany
| | - Joseph P Dewulf
- Department of Biochemistry, de Duve Institute, UCLouvain, Brussels, Belgium
- Walloon Excellence in Life Sciences and Biotechnology (WELBIO), Brussels, Belgium
- Department of Laboratory Medicine, Cliniques universitaires Saint-Luc, UCLouvain, Brussels, Belgium
| | - Guido T Bommer
- Department of Biochemistry, de Duve Institute, UCLouvain, Brussels, Belgium
- Walloon Excellence in Life Sciences and Biotechnology (WELBIO), Brussels, Belgium
| | - Daniel Hoces
- Institute of Food, Nutrition and Health, D-HEST, ETH Zurich, Zurich, Switzerland
| | - Valerie Gailus-Durner
- Institute of Experimental Genetics and German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Helmut Fuchs
- Institute of Experimental Genetics and German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Jan Rozman
- Institute of Experimental Genetics and German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - D Sean Froese
- Division of Metabolism and Children’s Research Center, University Children’s Hospital Zurich, University of Zurich, 8032 Zurich, Switzerland
- radiz – Rare Disease Initiative Zurich, Clinical Research Priority Program for Rare Diseases, University of Zurich, Zurich, Switzerland
| | - Matthias R Baumgartner
- Division of Metabolism and Children’s Research Center, University Children’s Hospital Zurich, University of Zurich, 8032 Zurich, Switzerland
- radiz – Rare Disease Initiative Zurich, Clinical Research Priority Program for Rare Diseases, University of Zurich, Zurich, Switzerland
- Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Martin Hrabě de Angelis
- Institute of Experimental Genetics and German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- Chair of Experimental Genetics, School of Life Science Weihenstephan, Technische Universität München, Freising, Germany
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Lynch E, Dempsey B, Saleeba C, Monteiro E, Turner A, Burke PGR, Allen AM, Dampney RAL, Hildreth CM, Cornish JL, Goodchild AK, McMullan S. Descending pathways from the superior colliculus mediating autonomic and respiratory effects associated with orienting behaviour. J Physiol 2022; 600:5311-5332. [PMID: 36271640 PMCID: PMC10107157 DOI: 10.1113/jp283789] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 10/14/2022] [Indexed: 01/05/2023] Open
Abstract
The ability to discriminate competing external stimuli and initiate contextually appropriate behaviours is a key brain function. Neurons in the deep superior colliculus (dSC) integrate multisensory inputs and activate descending projections to premotor pathways responsible for orienting, attention and defence, behaviours which involve adjustments to respiratory and cardiovascular parameters. However, the neural pathways that subserve the physiological components of orienting are poorly understood. We report that orienting responses to optogenetic dSC stimulation are accompanied by short-latency autonomic, respiratory and electroencephalographic effects in awake rats, closely mimicking those evoked by naturalistic alerting stimuli. Physiological responses were not accompanied by detectable aversion or fear, and persisted under urethane anaesthesia, indicating independence from emotional stress. Anterograde and trans-synaptic viral tracing identified a monosynaptic pathway that links the dSC to spinally projecting neurons in the medullary gigantocellular reticular nucleus (GiA), a key hub for the coordination of orienting and locomotor behaviours. In urethane-anaesthetized animals, sympathoexcitatory and cardiovascular, but not respiratory, responses to dSC stimulation were replicated by optogenetic stimulation of the dSC-GiA terminals, suggesting a likely role for this pathway in mediating the autonomic components of dSC-mediated responses. Similarly, extracellular recordings from putative GiA sympathetic premotor neurons confirmed short-latency excitatory inputs from the dSC. This pathway represents a likely substrate for autonomic components of orienting responses that are mediated by dSC neurons and suggests a mechanism through which physiological and motor components of orienting behaviours may be integrated without the involvement of higher centres that mediate affective components of defensive responses. KEY POINTS: Neurons in the deep superior colliculus (dSC) integrate multimodal sensory signals to elicit context-dependent innate behaviours that are accompanied by stereotypical cardiovascular and respiratory activities. The pathways responsible for mediating the physiological components of colliculus-mediated orienting behaviours are unknown. We show that optogenetic dSC stimulation evokes transient orienting, respiratory and autonomic effects in awake rats which persist under urethane anaesthesia. Anterograde tracing from the dSC identified projections to spinally projecting neurons in the medullary gigantocellular reticular nucleus (GiA). Stimulation of this pathway recapitulated autonomic effects evoked by stimulation of dSC neurons. Electrophysiological recordings from putative GiA sympathetic premotor neurons confirmed short latency excitatory input from dSC neurons. This disynaptic dSC-GiA-spinal sympathoexcitatory pathway may underlie autonomic adjustments to salient environmental cues independent of input from higher centres.
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Affiliation(s)
- Erin Lynch
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Bowen Dempsey
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Christine Saleeba
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Eloise Monteiro
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Anita Turner
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Peter G R Burke
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Andrew M Allen
- Department of Physiology, University of Melbourne, Victoria, Australia
| | - Roger A L Dampney
- School of Medical Sciences (Physiology), University of Sydney, Sydney, New South Wales, Australia
| | - Cara M Hildreth
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Jennifer L Cornish
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Ann K Goodchild
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Simon McMullan
- Macquarie Medical School, Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, New South Wales, Australia
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Antipov A, Brizuela M, Blessing WW, Ootsuka Y. Alpha 2-adrenergic receptor agonists prevent emotional hyperthermia. Brain Res 2020; 1732:146678. [PMID: 31981679 DOI: 10.1016/j.brainres.2020.146678] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 01/15/2020] [Accepted: 01/20/2020] [Indexed: 01/31/2023]
Abstract
Emotionally significant stimuli, including potential threats from the external environment, trigger an increase in body temperature, a response known as emotional hyperthermia. Sympathetically-mediated brown adipose tissue (BAT) thermogenesis contributes substantially to this hyperthermic response. The systemic administration of α2-adrenergic agonists is known to inhibit both febrile and shivering responses. In the present study, we investigated whether systemic administration of clonidine, a α2-adrenoceptor agonist, attenuates the emotional hyperthermia evoked in conscious unrestrained rats suddenly confronted with a second (intruder) rat, itself confined to a small cage. Pre-implanted thermistors were used to measure BAT and body temperature in conscious, freely moving, male Sprague-Dawley rats. The rats were pre-treated with intraperitoneally administered vehicle (Ringer solution) or clonidine (1, 10 and 100 µg/kg). Clonidine, in a dose-dependent manner, reduced the intruder-elicited increases in BAT (log-dose linear regression F(1,16) = 9.52, R2 = 0.37, P < 0.01) and body temperature (F(1,16) = 6.48, R2 = 0.29, P < 0.05). We also investigated, in anesthetized rats, whether systemic clonidine administration inhibits BAT sympathetic nerve discharge evoked via activation of neurons in the lateral habenula (LHb) - a nucleus involved in the regulation of emotional hyperthermia. In anesthetized rats, clonidine abolished the BAT sympathetic nerve discharges elicited via bicuculline-mediated disinhibition of the LHb. These results suggest that activation of central α2-adrenergic receptors attenuates the process of emotional hyperthermia by reduction of BAT thermogenesis.
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Affiliation(s)
- Anna Antipov
- Centre for Neuroscience, College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Mariana Brizuela
- Centre for Neuroscience, College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - William W Blessing
- Centre for Neuroscience, College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Youichirou Ootsuka
- Centre for Neuroscience, College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia.
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Duparcq M, Jean O, Verjat A, Jaravel L, Jacquet D, Robles Guerrero F, Féron C, Rödel HG. Differences between fast and slow explorers in short-term tail temperature responses to handling in a rodent of wild origin. Behav Brain Res 2019; 376:112194. [DOI: 10.1016/j.bbr.2019.112194] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 08/28/2019] [Accepted: 08/28/2019] [Indexed: 12/27/2022]
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Abstract
The lateral habenula (LHb) has an important role in the behavioural response to salient, usually aversive, events. We previously demonstrated that activation of neurons in the LHb increases brown adipose tissue (BAT) thermogenesis and constricts the cutaneous vascular bed, indicating that the LHb contributes to the central control of sympathetic outflow to thermoregulatory effector organs. We have now investigated whether the LHb mediates BAT thermogenesis elicited by emotional stress, and whether the LHb modulates thermoregulatory sympathetic outflow via the rostral medullary raphé, a key integrative lower brainstem sympathetic control centre. In conscious animals, lesioning the LHb attenuated emotional BAT thermogenesis, suggesting that the LHb is part of the central circuitry mediating emotional hyperthermia. In anesthetized animals, inhibition of neurons in the rostral medullary raphé reversed BAT thermogenesis and cutaneous vasoconstriction elicited by activation of neurons in the LHb, indicating that the LHb-induced autonomic responses are mediated through activation of the rostral medullary raphé neurons. The latency to activate BAT sympathetic discharge from electrical stimulation of the LHb was substantially greater than the corresponding latency after stimulation of the medullary raphé, suggesting that the neuronal pathway connecting those two nuclei is quite indirect.
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Blessing W, McAllen R, McKinley M. Control of the Cutaneous Circulation by the Central Nervous System. Compr Physiol 2016; 6:1161-97. [PMID: 27347889 DOI: 10.1002/cphy.c150034] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The central nervous system (CNS), via its control of sympathetic outflow, regulates blood flow to the acral cutaneous beds (containing arteriovenous anastomoses) as part of the homeostatic thermoregulatory process, as part of the febrile response, and as part of cognitive-emotional processes associated with purposeful interactions with the external environment, including those initiated by salient or threatening events (we go pale with fright). Inputs to the CNS for the thermoregulatory process include cutaneous sensory neurons, and neurons in the preoptic area sensitive to the temperature of the blood in the internal carotid artery. Inputs for cognitive-emotional control from the exteroceptive sense organs (touch, vision, sound, smell, etc.) are integrated in forebrain centers including the amygdala. Psychoactive drugs have major effects on the acral cutaneous circulation. Interoceptors, chemoreceptors more than baroreceptors, also influence cutaneous sympathetic outflow. A major advance has been the discovery of a lower brainstem control center in the rostral medullary raphé, regulating outflow to both brown adipose tissue (BAT) and to the acral cutaneous beds. Neurons in the medullary raphé, via their descending axonal projections, increase the discharge of spinal sympathetic preganglionic neurons controlling the cutaneous vasculature, utilizing glutamate, and serotonin as neurotransmitters. Present evidence suggests that both thermoregulatory and cognitive-emotional control of the cutaneous beds from preoptic, hypothalamic, and forebrain centers is channeled via the medullary raphé. Future studies will no doubt further unravel the details of neurotransmitter pathways connecting these rostral control centers with the medullary raphé, and those operative within the raphé itself. © 2016 American Physiological Society. Compr Physiol 6:1161-1197, 2016.
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Affiliation(s)
- William Blessing
- Human Physiology, Centre for Neuroscience, Flinders University, Adelaide, S.A., Australia
| | - Robin McAllen
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Vic., Australia
| | - Michael McKinley
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Vic., Australia
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Mohammed M, Yanagisawa M, Blessing W, Ootsuka Y. Attenuated cold defense responses in orexin neuron-ablated rats. Temperature (Austin) 2016; 3:465-475. [PMID: 28349086 PMCID: PMC5079225 DOI: 10.1080/23328940.2016.1184366] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 04/21/2016] [Accepted: 04/22/2016] [Indexed: 12/13/2022] Open
Abstract
Recent reports of the use of transgenic mice targeting orexin neurons show that the ablation of orexin neurons in the hypothalamus causes hypothermia during cold exposure. This suggests the importance of orexin neurons for cold-induced autonomic and physiological defense responses, including brown adipose tissue (BAT) thermogenesis and vasoconstriction in thermoregulatory cutaneous vascular bed. The present study investigated whether the ablation of orexin neurons attenuated cold-elicited BAT thermogenesis and cutaneous vasoconstriction. The study took advantage of our established conscious rat experimental model of direct measurement of BAT and body temperature and tail cutaneous blood flow. The study used transgenic orexin neurons-ablated (ORX-AB) rats and wild type (WT) rats. BAT temperature and tail artery blood flow with pre-implanted probes were measured, as well as behavioral locomotor activity under conscious free-moving condition. Gradually, the ambient temperature was decreased to below 5°C. ORX-AB rats showed an attenuated cold-induced BAT thermogenesis and behavioral activity, and delayed tail vasoconstriction. An ambient temperature that initiated BAT thermogenesis and established full cutaneous vasoconstriction was 14.1 ± 1.9 °C, which was significantly lower than 20.5 ± 1.9 °C, the corresponding value in WT rats (n = 10, P < 0.01). The results from this study suggest that the integrity of orexin-synthesising neurons in thermoregulatory networks is important for full expression of the cold defense responses.
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Affiliation(s)
- Mazher Mohammed
- Centre for Neuroscience, Department of Human Physiology, Flinders University , Adelaide, SA, Australia
| | - Masashi Yanagisawa
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Japan; Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - William Blessing
- Centre for Neuroscience, Department of Human Physiology, Flinders University , Adelaide, SA, Australia
| | - Youichirou Ootsuka
- Centre for Neuroscience, Department of Human Physiology, Flinders University , Adelaide, SA, Australia
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Mohammed M, Kulasekara K, Ootsuka Y, Blessing WW. Locus coeruleus noradrenergic innervation of the amygdala facilitates alerting-induced constriction of the rat tail artery. Am J Physiol Regul Integr Comp Physiol 2016; 310:R1109-19. [PMID: 27101292 DOI: 10.1152/ajpregu.00058.2016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 04/11/2016] [Indexed: 02/08/2023]
Abstract
The amygdala, innervated by the noradrenergic locus coeruleus, processes salient environmental events. α2-adrenoceptor-stimulating drugs (clonidine-like agents) suppress the behavioral and physiological components of the response to salient events. Activation of sympathetic outflow to the cutaneous vascular bed is part of the physiological response to salience-mediated activation of the amygdala. We have determined whether acute systemic and intra-amygdala administration of clonidine, and chronic immunotoxin-mediated destruction of the noradrenergic innervation of the amygdala, impairs salience-related vasoconstrictor episodes in the tail artery of conscious freely moving Sprague-Dawley rats. After acute intraperitoneal injection of clonidine (10, 50, and 100 μg/kg), there was a dose-related decrease in the reduction in tail blood flow elicited by alerting stimuli, an effect prevented by prior administration of the α2-adrenergic blocking drug idazoxan (1 mg/kg ip or 75 nmol bilateral intra-amygdala). A dose-related decrease in alerting-induced tail artery vasoconstriction was also observed after bilateral intra-amygdala injection of clonidine (5, 10, and 20 nmol in 200 nl), an effect substantially prevented by prior bilateral intra-amygdala injection of idazoxan. Intra-amygdala injection of idazoxan by itself did not alter tail artery vasoconstriction elicited by alerting stimuli. Intra-amygdala injection of saporin coupled to antibodies to dopamine-β-hydroxylase (immunotoxin) destroyed the noradrenergic innervation of the amygdala and the parent noradrenergic neurons in the locus coeruleus. The reduction in tail blood flow elicited by standardized alerting stimuli was substantially reduced in immunotoxin-treated rats. Thus, inhibiting the release of noradrenaline within the amygdala reduces activation of the sympathetic outflow to the vascular beds elicited by salient events.
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Affiliation(s)
- Mazher Mohammed
- Centre for Neuroscience, Department of Human Physiology, Flinders University, Adelaide, South Australia, Australia
| | - Keerthi Kulasekara
- Centre for Neuroscience, Department of Human Physiology, Flinders University, Adelaide, South Australia, Australia
| | - Youichirou Ootsuka
- Centre for Neuroscience, Department of Human Physiology, Flinders University, Adelaide, South Australia, Australia
| | - William W Blessing
- Centre for Neuroscience, Department of Human Physiology, Flinders University, Adelaide, South Australia, Australia
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Lecorps B, Rödel HG, Féron C. Assessment of anxiety in open field and elevated plus maze using infrared thermography. Physiol Behav 2016; 157:209-16. [PMID: 26884121 DOI: 10.1016/j.physbeh.2016.02.014] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 02/06/2016] [Accepted: 02/09/2016] [Indexed: 10/22/2022]
Abstract
Due to their direct inaccessibility, affective states are classically assessed by gathering concomitant physiological and behavioral measures. Although such a dual approach to assess emotional states is frequently used in different species including humans, the invasiveness of procedures for physiological recordings particularly in smaller-sized animals strongly restricts their application. We used infrared thermography, a non-invasive method, to assess physiological arousal during open field and elevated plus maze tests in mice. By measuring changes in surface temperature indicative of the animals' emotional response, we aimed to improve the inherently limited and still controversial information provided by behavioral parameters commonly used in these tests. Our results showed significant and consistent thermal responses during both tests, in accordance with classical physiological responses occurring in stressful situations. Besides, we found correlations between these thermal responses and the occurrence of anxiety-related behaviors. Furthermore, initial temperatures measured at the start of each procedure (open field, elevated plus maze), which can be interpreted as a measure of the animals' initial physiological arousal, predicted the levels of activity and of anxiety-related behaviors displayed during the tests. Our results stress the strong link between physiological correlates of emotions and behaviors expressed during unconditioned fear tests.
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Affiliation(s)
- Benjamin Lecorps
- Laboratoire d'Ethologie Expérimentale et Comparée E.A. 4443 (LEEC), Université Paris 13, Sorbonne Paris Cité, F-93430 Villetaneuse, France.
| | - Heiko G Rödel
- Laboratoire d'Ethologie Expérimentale et Comparée E.A. 4443 (LEEC), Université Paris 13, Sorbonne Paris Cité, F-93430 Villetaneuse, France
| | - Christophe Féron
- Laboratoire d'Ethologie Expérimentale et Comparée E.A. 4443 (LEEC), Université Paris 13, Sorbonne Paris Cité, F-93430 Villetaneuse, France
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Ootsuka Y, Tanaka M. Control of cutaneous blood flow by central nervous system. Temperature (Austin) 2015; 2:392-405. [PMID: 27227053 PMCID: PMC4843916 DOI: 10.1080/23328940.2015.1069437] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 06/26/2015] [Accepted: 07/01/2015] [Indexed: 02/07/2023] Open
Abstract
Hairless skin acts as a heat exchanger between body and environment, and thus greatly contributes to body temperature regulation by changing blood flow to the skin (cutaneous) vascular bed during physiological responses such as cold- or warm-defense and fever. Cutaneous blood flow is also affected by alerting state; we 'go pale with fright'. The rabbit ear pinna and the rat tail have hairless skin, and thus provide animal models for investigating central pathway regulating blood flow to cutaneous vascular beds. Cutaneous blood flow is controlled by the centrally regulated sympathetic nervous system. Sympathetic premotor neurons in the medullary raphé in the lower brain stem are labeled at early stage after injection of trans-synaptic viral tracer into skin wall of the rat tail. Inactivation of these neurons abolishes cutaneous vasomotor changes evoked as part of thermoregulatory, febrile or psychological responses, indicating that the medullary raphé is a common final pathway to cutaneous sympathetic outflow, receiving neural inputs from upstream nuclei such as the preoptic area, hypothalamic nuclei and the midbrain. Summarizing evidences from rats and rabbits studies in the last 2 decades, we will review our current understanding of the central pathways mediating cutaneous vasomotor control.
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Affiliation(s)
- Youichirou Ootsuka
- Centre for Neuroscience; Department of Human Physiology; School of Medicine; Flinders University; Bedford Park; South Australia, Australia
- Department of Physiology; Graduate School of Medical and Dental Sciences; Kagoshima University; Kagoshima, Japan
| | - Mutsumi Tanaka
- Health Effects Research Group; Energy and Environment Research Division; Japan Automobile Research Institute; Tsukuba, Ibaraki, Japan
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Ootsuka Y, Mohammed M. Activation of the habenula complex evokes autonomic physiological responses similar to those associated with emotional stress. Physiol Rep 2015; 3:3/2/e12297. [PMID: 25677551 PMCID: PMC4393205 DOI: 10.14814/phy2.12297] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Neurons in the lateral habenula (LHb) discharge when an animal anticipates an aversive outcome or when an expected reward is not forthcoming, contributing to the behavioral response to aversive situations. So far, there is little information as to whether the LHb also contributes to autonomic physiological responses, including increases in body temperature (emotional hyperthermia) that are integrated with defensive behaviors. Vasoconstriction in cutaneous vascular bed and heat production in brown adipose tissue (BAT) both contribute to emotional hyperthermia. Our present study determines whether stimulation of the LHb elicits constriction of the tail artery and BAT thermogenesis in anesthetized Sprague–Dawley rats. Disinhibition of neurons in LHb with focal microinjections of bicuculline (1 nmol in 100 nl, bilaterally) acutely increased BAT temperature (+0.6 ± 0.1°C, n = 9 rats, P < 0.01) and reduced tail artery blood flow (by 88 ± 4%, n = 9 rats, P < 0.01). Falls in mesenteric blood flow, simultaneously recorded, were much less intense. The pattern of BAT thermogenesis and cutaneous vasoconstriction elicited by stimulating the habenula is similar to the pattern observed during stress-induced emotional hyperthermia, suggesting that the habenula may be important in this response.
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Affiliation(s)
- Youichirou Ootsuka
- Centre for Neuroscience, Department of Human Physiology, Flinders University, Adelaide, South Australia, Australia
| | - Mazher Mohammed
- Centre for Neuroscience, Department of Human Physiology, Flinders University, Adelaide, South Australia, Australia
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Mohammed M, Ootsuka Y, Yanagisawa M, Blessing W. Reduced brown adipose tissue thermogenesis during environmental interactions in transgenic rats with ataxin-3-mediated ablation of hypothalamic orexin neurons. Am J Physiol Regul Integr Comp Physiol 2014; 307:R978-89. [PMID: 25324552 DOI: 10.1152/ajpregu.00260.2014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Thermogenesis in brown adipose tissue (BAT) contributes to substantial increases in body temperature evoked by threatening or emotional stimuli. BAT thermogenesis also contributes to increases in body temperature that occur during active phases of the basic rest-activity cycle (BRAC), as part of normal daily life. Hypothalamic orexin-synthesizing neurons influence many physiological and behavioral variables, including BAT and body temperature. In conscious unrestrained animals maintained for 3 days in a quiet environment (24-26°C) with ad libitum food and water, we compared temperatures in transgenic rats with ablation of orexin neurons induced by expression of ataxin-3 (Orx_Ab) with wild-type (WT) rats. Both baseline BAT temperature and baseline body temperature, measured at the onset of BRAC episodes, were similar in Orx_Ab and WT rats. The time interval between BRAC episodes was also similar in the two groups. However, the initial slopes and amplitudes of BRAC-related increases in BAT and body temperature were reduced in Orx_Ab rats. Similarly, the initial slopes and amplitudes of the increases in BAT temperatures induced by sudden exposure to an intruder rat (freely moving or confined to a small cage) or by sudden exposure to live cockroaches were reduced in resident Orx_Ab rats. Constriction of the tail artery induced by salient alerting stimuli was also reduced in Orx_Ab rats. Our results suggest that orexin-synthesizing neurons contribute to the intensity with which rats interact with the external environment, both when the interaction is "spontaneous" and when the interaction is provoked by threatening or salient environmental events.
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Affiliation(s)
- Mazher Mohammed
- Centre for Neuroscience, Department of Human Physiology, Flinders University, Adelaide, South Australia, Australia; and
| | - Youichirou Ootsuka
- Centre for Neuroscience, Department of Human Physiology, Flinders University, Adelaide, South Australia, Australia; and
| | - Masashi Yanagisawa
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Japan; and Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas
| | - William Blessing
- Centre for Neuroscience, Department of Human Physiology, Flinders University, Adelaide, South Australia, Australia; and
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El Bitar N, Pollin B, Le Bars D. "On-" and "off-" cells in the rostral ventromedial medulla of rats held in thermoneutral conditions: are they involved in thermoregulation? J Neurophysiol 2014; 112:2199-217. [PMID: 25008415 DOI: 10.1152/jn.00722.2013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In thermal neutral condition, rats display cyclic variations of the vasomotion of the tail and paws, synchronized with fluctuations of blood pressure, heart rate, and core body temperature. "On-" and "off-" cells located in the rostral ventromedial medulla, a cerebral structure implicated in somatic sympathetic drive, 1) exhibit similar spontaneous cyclic activities in antiphase and 2) are activated and inhibited by thermal nociceptive stimuli, respectively. We aimed at evaluating the implication of such neurons in autonomic regulation by establishing correlations between their firing and blood pressure, heart rate, and skin and core body temperature variations. When, during a cycle, a relative high core body temperature was reached, the on-cells were activated and within half a minute, the off-cells and blood pressure were depressed, followed by heart rate depression within a further minute; vasodilatation of the tail followed invariably within ∼3 min, often completed with vasodilatation of hind paws. The outcome was an increased heat loss that lessened the core body temperature. When the decrease of core body temperature achieved a few tenths of degrees, sympathetic activation switches off and converse variations occurred, providing cycles of three to seven periods/h. On- and off-cell activities were correlated with inhibition and activation of the sympathetic system, respectively. The temporal sequence of events was as follows: core body temperature → on-cell → off-cell ∼ blood pressure → heart rate → skin temperature → core body temperature. The function of on- and off-cells in nociception should be reexamined, taking into account their correlation with autonomic regulations.
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Affiliation(s)
- Nabil El Bitar
- Sorbonne Universités, Université Pierre et Marie Curie, Université Paris 06, Faculté de Médecine, Paris, France; and Neurosciences Paris-Seine, Institut National de la Santé et de la Recherche Médicale UMRS-1130, Centre National de la Recherche Scientifique UMR-8246, Paris, France
| | - Bernard Pollin
- Sorbonne Universités, Université Pierre et Marie Curie, Université Paris 06, Faculté de Médecine, Paris, France; and Neurosciences Paris-Seine, Institut National de la Santé et de la Recherche Médicale UMRS-1130, Centre National de la Recherche Scientifique UMR-8246, Paris, France
| | - Daniel Le Bars
- Sorbonne Universités, Université Pierre et Marie Curie, Université Paris 06, Faculté de Médecine, Paris, France; and Neurosciences Paris-Seine, Institut National de la Santé et de la Recherche Médicale UMRS-1130, Centre National de la Recherche Scientifique UMR-8246, Paris, France
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Mohammed M, Ootsuka Y, Blessing W. Brown adipose tissue thermogenesis contributes to emotional hyperthermia in a resident rat suddenly confronted with an intruder rat. Am J Physiol Regul Integr Comp Physiol 2014; 306:R394-400. [PMID: 24452545 PMCID: PMC3949111 DOI: 10.1152/ajpregu.00475.2013] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Body temperature increases when individuals experience salient, emotionally significant events. There is controversy concerning the contribution of nonshivering thermogenesis in brown adipose tissue (BAT) to emotional hyperthermia. In the present study we compared BAT, core body, and brain temperature, and tail blood flow, simultaneously measured, to determine whether BAT thermogenesis contributes to emotional hyperthermia in a resident Sprague-Dawley rat when an intruder rat, either freely-moving or confined to a small cage, is suddenly introduced into the cage of the resident rat for 30 min. Introduction of the intruder rat promptly increased BAT, body, and brain temperatures in the resident rat. For the caged intruder these temperature increases were 1.4 ± 0.2, 0.8 ± 0.1, 1.0 ± 0.1°C, respectively, with the increase in BAT temperature being significantly greater (P < 0.01) than the increases in body and brain. The initial 5-min slope of the BAT temperature record (0.18 ± 0.02°C/min) was significantly greater (P < 0.01) than the corresponding value for body (0.10 ± 0.01°C/min) and brain (0.09 ± 0.02°C/min). Tail artery pulse amplitude fell acutely when the intruder rat was introduced, possibly contributing to the increases in body and brain temperature. Prior blockade of β3 adrenoceptors (SR59230A 10 mg/kg ip) significantly reduced the amplitude of each temperature increase. Intruder-evoked increases in BAT temperature were similar in resident rats maintained at 11°C for 3 days. In the caged intruder situation there is no bodily contact between the rats, so the stimulus is psychological rather than physical. Our study thus demonstrates that BAT thermogenesis contributes to increases in body and brain temperature occurring during emotional hyperthermia.
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Affiliation(s)
- Mazher Mohammed
- Department of Human Physiology, Flinders University, Adelaide, South Australia, Australia
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15
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Brown adipose tissue thermogenesis, the basic rest–activity cycle, meal initiation, and bodily homeostasis in rats. Physiol Behav 2013; 121:61-9. [DOI: 10.1016/j.physbeh.2013.03.028] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 03/12/2013] [Accepted: 03/19/2013] [Indexed: 11/18/2022]
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Inactivation of neuronal function in the amygdaloid region reduces tail artery blood flow alerting responses in conscious rats. Neuroscience 2013; 228:13-22. [DOI: 10.1016/j.neuroscience.2012.10.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Revised: 10/02/2012] [Accepted: 10/03/2012] [Indexed: 11/19/2022]
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Dacks PA, Krajewski SJ, Rance NE. Activation of neurokinin 3 receptors in the median preoptic nucleus decreases core temperature in the rat. Endocrinology 2011; 152:4894-905. [PMID: 22028440 PMCID: PMC3230049 DOI: 10.1210/en.2011-1492] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 09/22/2011] [Indexed: 11/19/2022]
Abstract
Estrogens have pronounced effects on thermoregulation, as illustrated by the occurrence of hot flushes secondary to estrogen withdrawal in menopausal women. Because neurokinin B (NKB) gene expression is markedly increased in the infundibular (arcuate) nucleus of postmenopausal women, and is modulated by estrogen withdrawal and replacement in multiple species, we have hypothesized that NKB neurons could play a role in the generation of flushes. There is no information, however, on whether the primary NKB receptor [neurokinin 3 receptor (NK(3)R)] modulates body temperature in any species. Here, we determine the effects of microinfusion of a selective NK(3)R agonist (senktide) into the rat median preoptic nucleus (MnPO), an important site in the heat-defense pathway. Senktide microinfusion into the rat MnPO decreased core temperature in a dose-dependent manner. The hypothermia induced by senktide was similar in ovariectomized rats with and without 17β-estradiol replacement. The hypothermic effect of senktide was prolonged in rats exposed to an ambient temperature of 29.0 C, compared with 21.5 C. Senktide microinfusion also altered tail skin vasomotion in rats exposed to an ambient temperature of 29.0 but not 21.5 C. Comparisons of the effects of senktide at different ambient temperatures indicated that the hypothermia was not secondary to thermoregulatory failure or a reduction in cold-induced thermogenesis. Other than a very mild increase in drinking, senktide microinfusion did not affect behavior. Terminal fluorescent dextran microinfusion showed targeting of the MnPO and adjacent septum, and immunohistochemical studies revealed that senktide induced a marked increase in Fos-activation in the MnPO. Because MnPO neurons expressed NK(3)R-immunoreactivity, the induction of MnPO Fos by senktide is likely a direct effect. By demonstrating that NK(3)R activation in the MnPO modulates body temperature, these studies support the hypothesis that hypothalamic NKB neurons could be involved in the generation of menopausal flushes.
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Affiliation(s)
- Penny A Dacks
- Department of Pathology, University of Arizona College of Medicine, 1501 North Campbell Avenue, Tucson, Arizona 85724, USA
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Blessing W, Mohammed M, Ootsuka Y. Heating and eating: brown adipose tissue thermogenesis precedes food ingestion as part of the ultradian basic rest-activity cycle in rats. Physiol Behav 2011; 105:966-74. [PMID: 22115948 DOI: 10.1016/j.physbeh.2011.11.009] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Revised: 10/19/2011] [Accepted: 11/07/2011] [Indexed: 11/18/2022]
Abstract
Laboratory rats, throughout the 24 hour day, alternate between behaviorally active and non active episodes that Kleitman called the basic rest-activity cycle (BRAC). We previously demonstrated that brown adipose tissue (BAT), body and brain temperatures and arterial pressure and heart rate increase in an integrated manner during behaviorally active phases. Studies show that eating is preceded by increases in body and brain temperature, but whether eating is integrated into the BRAC has not been investigated. In the present study of chronically instrumented, unrestrained Sprague-Dawley rats, peaks in BAT temperature occurred every 96 ± 7 and 162 ± 16 min (mean ± SE, n=14 rats) in dark and light periods respectively, with no apparent underlying regularity. With food available ad libitum, eating was integrated into the BRAC in a temporally precise manner. Eating occurred only after an increase in BAT temperature, commencing 15 ± 1 min (mean ± SE) after the onset of an increase, with no difference between dark and light phases. There were either no or weak preprandial and postprandial relations between intermeal interval and amount eaten during a given meal. Remarkably, with no food available the rat still disturbed the empty food container 16 ± 1 min (p>0.05 versus ad libitum food) after the onset of increases in BAT temperature, and not at other times. Rather than being triggered by changes in levels of body fuels or other meal-associated factors, in sedentary laboratory rats with ad libitum access to food eating commences as part of the ultradian BRAC, a manifestation of intrinsic brain activity.
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Affiliation(s)
- William Blessing
- Centre for Neuroscience, Department of Human Physiology, Flinders University, Adelaide, SA 5042, Australia.
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Ootsuka Y, Kulasekara K, de Menezes RC, Blessing WW. SR59230A, a beta-3 adrenoceptor antagonist, inhibits ultradian brown adipose tissue thermogenesis and interrupts associated episodic brain and body heating. Am J Physiol Regul Integr Comp Physiol 2011; 301:R987-94. [PMID: 21813867 DOI: 10.1152/ajpregu.00085.2011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Brown adipose tissue (BAT) thermogenesis occurs episodically in an ultradian manner approximately every 80-100 min during the waking phase of the circadian cycle, together with highly correlated increases in brain and body temperatures, suggesting that BAT thermogenesis contributes to brain and body temperature increases. We investigated this in conscious Sprague-Dawley rats by determining whether inhibition of BAT thermogenesis via blockade of beta-3 adrenoceptors with SR59230A interrupts ultradian episodic increases in brain and body temperatures and whether SR59230A acts on BAT itself or via sympathetic neural control of BAT. Interscapular BAT (iBAT), brain, and body temperatures, tail artery blood flow, and heart rate were measured in unrestrained rats. SR59230A (1, 5, or 10 mg/kg ip), but not vehicle, decreased iBAT, body, and brain temperatures in a dose-dependent fashion (log-linear regression P < 0.01, R(2) = 0.3, 0.4, and 0.4, respectively, n = 10). Ultradian increases in BAT, brain, and body temperature were interrupted by administration of SR59230A (10 mg/kg ip) compared with vehicle, resuming after 162 ± 24 min (means ± SE, n = 10). SR59230A (10 mg/kg ip) caused a transient bradycardia without any increase in tail artery blood flow. In anesthetized rats, SR59230A reduced cooling-induced increases in iBAT temperature without affecting cooling-induced increases in iBAT sympathetic nerve discharge. Inhibition of BAT thermogenesis by SR59230A, thus, reflects direct blockade of beta-3 adrenoceptors in BAT. Interruption of episodic ultradian increases in body and brain temperature by SR59230A suggests that BAT thermogenesis makes a substantial contribution to these increases.
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Affiliation(s)
- Youichirou Ootsuka
- Centre for Neuroscience, Department of Human Physiology, Flinders University, Adelaide, South Australia, Australia.
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Blessing E, Kader L, Arpandy R, Ootsuka Y, Blessing WW, Pantelis C. Atypical antipsychotics cause an acute increase in cutaneous hand blood flow in patients with schizophrenia and schizoaffective disorder. Aust N Z J Psychiatry 2011; 45:646-53. [PMID: 21870922 DOI: 10.3109/00048674.2011.587397] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Clinical studies suggest resting thermoregulatory cutaneous vasomotor tone could be increased in schizophrenia, resulting in reduced hand blood flow. In animal models, atypical antipsychotics including clozapine potently inhibit sympathetic neural outflow to the thermoregulatory cutaneous vascular beds. We have now determined whether antipsychotic medication administration is associated with an acute increase in hand blood flow in patients with schizophrenia and schizoaffective disorder, and whether this increase correlates with clinical status. METHOD Hand temperature was measured with an infrared camera in 12 patients with chronic schizophrenia or schizoaffective disorder 30 min prior to, then 30 and 60 min following medication. Clinical status was assessed via the Brief Psychiatric Rating Scale (BPRS). Results were compared using regression and repeated measures analysis of variance. RESULTS A robust and significant increase in hand temperature (p < 0.001) was observed following antipsychotic administration. The mean increase after 60 min was 4.1 ± 2.4°C. This increase was significantly associated with colder hand temperature prior to medication (p < 0.05; suggestive of increased resting vasoconstriction) and with more severe psychiatric symptoms (p < 0.05). CONCLUSIONS Atypical antipsychotics were associated with increased hand blood flow, consistent with inhibition of thermoregulatory sympathetic outflow to the cutaneous vascular bed in patients with schizophrenia and schizoaffective disorder. This increase correlated with symptom severity. Hand temperature increase following antipsychotic medication may therefore be a simple and informative physiological marker of disease activity and potential response in patients with schizophreniform disorders. Given that antipsychotics also inhibit sympathetic outflow to brown adipose tissue, which normally converts energy to heat, future studies should examine whether antipsychotic-induced hand temperature increase is associated with antipsychotic-induced weight gain.
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Affiliation(s)
- Esther Blessing
- Department of Psychiatry, University of Melbourne, St. Vincent's Hospital, Fitzroy, Victoria 3065, Australia.
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Sensory mismatch induces autonomic responses associated with hippocampal theta waves in rats. Behav Brain Res 2011; 220:244-53. [PMID: 21316395 DOI: 10.1016/j.bbr.2011.02.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2010] [Revised: 01/30/2011] [Accepted: 02/06/2011] [Indexed: 11/23/2022]
Abstract
Hippocampal (HIP) theta power increases during sensory mismatch, which has been suggested to induce motion sickness with autonomic abnormality (Zou et al., 2009 [29]). To investigate relationships between hippocampal theta rhythm and autonomic functions, theta waves in the HIP and electrocardiograms (ECGs) were recorded during sensory mismatch by backward translocation in awake rats. The rats were placed on a treadmill affixed to a motion stage that was translocated along a figure 8-shaped track. The rats were trained to run forward on the treadmill at the same speed as that of forward translocation of the motion stage (a forward condition) before the experimental (recording) sessions. In the experimental sessions, the rats were initially tested in the forward condition, and then tested in a backward (mismatch) condition, in which the motion stage was turned around by 180° before translocation. That is, the rats were moved backward by translocation of the stage although the rats ran forward on the treadmill. In this condition, proprioceptive information indicated forward movements while vestibular and visual information indicated backward movements. The theta (6-9 Hz) power was significantly increased in the backward condition compared with the forward condition. Spectral analysis of heart rate variability indicated that sympathetic nervous activity increased in the backward condition. These data (theta power and sympathetic nervous activity) were positively correlated. Furthermore, electrical stimulation of the HIP at theta rhythm (8 Hz) increased heart rate. These results suggest that sensory mismatch information activates the HIP to induce autonomic alteration in motion sickness.
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Carrive P, Churyukanov M, Le Bars D. A reassessment of stress-induced "analgesia" in the rat using an unbiased method. Pain 2011; 152:676-686. [PMID: 21277086 DOI: 10.1016/j.pain.2010.12.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Revised: 12/02/2010] [Accepted: 12/13/2010] [Indexed: 12/01/2022]
Abstract
An increased tail-flick latency to noxious heat during or after stress in the rodent is usually interpreted as a stress-induced reduction in pain sensitivity and often described as a form of stress-induced "analgesia." However, this measure is an indirect and flawed measure of the change in nociceptive threshold to noxious heat. A major confound of the latency measure is the initial temperature of the tail, which can drop down to room temperature during stress, the consequence of a marked sympathetically mediated vasoconstriction in the skin of the extremities. We addressed this issue with tail-flick tests during contextual fear using infrared thermography to monitor temperature changes and a CO2 laser to deliver the heat stimulus. The experiment revealed a 4.2°C increase of the nociceptive threshold, confirming a true antinociceptive effect. However, its contribution to the increased withdrawal latency was less than two-thirds (63.2%). Nearly one-third (32.2%) was due to the drop in tail temperature (4.4°C), which also slowed conduction along sensory fibers (2.2%, included in the 32.2%). The remaining 4.6% was due to an increase in decisional/motor latency. This new unbiased method establishes beyond doubt that a conditioned stress response is associated with true antinociception to noxious heat. It also confirms that stress-induced changes in skin temperature can be a major confound in tail-flick tests. The present study shows, for the first time, the exact contribution of these two components of the tail-flick latency for a stress response. Less than two-thirds of the increase in tail-flick latency to noxious heat, evoked by conditioned fear, reflects true antinociception. The remaining is due to skin vasoconstriction.
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Affiliation(s)
- Pascal Carrive
- School of Medical Sciences, University of New South Wales, NSW 2052, Australia Department of Neurology, Moscow Medical Academy, Moscow 119021, Russia Team "Pain", INSERM UMRS 975, CNRS UMR 7225, Faculté de Médecine UPMC, Université Pierre et Marie Curie, Paris, France
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Sleep deprivation impairs spatial learning and modifies the hippocampal theta rhythm in rats. Neuroscience 2011; 173:116-23. [DOI: 10.1016/j.neuroscience.2010.11.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Revised: 10/14/2010] [Accepted: 11/02/2010] [Indexed: 11/18/2022]
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Capuano B, Crosby IT, McRobb FM, Taylor DA, Vom A, Blessing WW. JL13 has clozapine-like actions on thermoregulatory cutaneous blood flow in rats: Involvement of serotonin 5-HT1A and 5-HT2A receptor mechanisms. Prog Neuropsychopharmacol Biol Psychiatry 2010; 34:136-42. [PMID: 19878703 DOI: 10.1016/j.pnpbp.2009.10.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Revised: 10/18/2009] [Accepted: 10/20/2009] [Indexed: 11/25/2022]
Abstract
Clozapine is an effective atypical antipsychotic agent, with serious side effects. JL13 [5-(4-methylpiperazin-1-yl)-8-chloropyrido[2,3-b][1,5]benzoxazepine] is a potential new atypical antipsychotic, structurally modified from clozapine to resist oxidation so as to reduce haematological and cardiological side effects. To assess the potential clinical potency of JL13 we tested its action in a newly described animal model based on the ability of clozapine-like agents to affect brain mechanisms controlling sympathetic outflow to thermoregulatory cutaneous vascular beds. We determined whether JL13 has clozapine-like inhibitory actions on alerting-induced falls in tail artery blood flow (sympathetic cutaneous vasomotor alerting responses, SCVARs) in rats, and whether actions on dopamine D(2), and/or 5-HT(1A) receptors are involved in these effects of JL13. The tail artery Doppler flow signal was recorded in conscious freely moving Sprague-Dawley rats before and after alerting stimuli (e.g. cage tap). The percentage fall in flow in response to an alerting stimulus was quantified as a SCVAR index (fall to zero flow implies SCVAR index of 100%, no fall implies 0%). We used pre-treatment with spiperone and WAY100635, before JL13, to assess the role of D(2) and 5-HT(1A) receptors. In addition, the role of 5-HT(2A) receptors in the action of JL13 was assessed by determining whether JL13 prevented and reversed the CNS-mediated tail artery vasoconstricting actions of DOI ((+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane), an agonist at 5-HT(2A) receptors. JL13 (0.0625-5.0mg/kg s.c.) dose-dependently inhibited SCVARs, less potently than clozapine. WAY100635 but not spiperone reduced the inhibition. JL13 prevented and reversed DOI-induced vasoconstriction. Thus JL13 has clozapine-like actions on thermoregulatory cutaneous blood flow, but the drug is 5 times less potent than clozapine. Stimulation of 5-HT(1A) and blockade of 5-HT(2A) receptors may contribute to the effects, but dopamine D(2) receptors are apparently not involved in the action of JL13.
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Affiliation(s)
- B Capuano
- Medicinal Chemistry & Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), Melbourne, Australia
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